well no wonder. you are using the ones with the larger pivot hole. those should work anywhere that you can use a kadee #5. I wasn't aware they still made those. I must have thrown out hundreds of those over the years. I can say I have not seen these in a hobby shop recently.

JB, on some modern locomotives you can get away with the old Athearn X2F/Horn-Hook couplers. However, that is not always the case, and I can think of a lot of locomotives off the top of my head that would be extremely difficult or impossible to install X2F couplers. It also does not help matters that the Athearn X2F couplers were not available from Horizon and going to be discontinued in the near future when whatever is left of the couplers is depleted. At which point that would leave you in a bind and with no recourse once you run out of the Athearn X2F couplers because the other manufacturers couplers are not made with the centering spring but rather snap into the talgo trucks found on Life-Like cars. Also there also many pieces of rolling stock that I c as n think of that cannot be converted to X2F couplers. Basically any locomotive or piece of rolling stock that requires long shank couplers would be impossible to convert in almost every case. Any locomotive or piece of rolling stock that has an NEM coupler box, Rivarossi for instance, cannot be converted to X2F couplers because the X2F couplers made to go in NEM coupler boxes have been out of production for over 10 years now, and tge tooling does not exist anymore. So once all old stock was depleted at your local hobby shops if they even have any left, you would have no choice but to utilize a mchenry knuckle coupler because it is the only coupler still in production that fits in NEM boxes. Of course you could break or cut off the NEM box and probably lose some detail pieces in the process but you would be stupid to do so because it would permanently void your warranty. In short you can definitely get away with using the Athearn X2F couplers on some locomotives and rolling stock, however, there are many cases where conversion to X2F couplers is not practical or possible and you will end up causing more trouble for yourself in the long term when the Athearn couplers are out of production.

JB, the question is why spend the time to bother, instead of taking the same time to convert to knuckle couplers? Maybe, instead of constantly buying more cars to have every week for COTW, it would better to spend the resources on conversions...

I have not seen these in a hobby shop recently.

Jeff you need to look outside the LHS, there is a whole great big world out there.